This application relates generally to gas turbine engines and, more particularly, to combustors for gas turbine engine.
Combustors are used to ignite fuel and air mixtures in gas turbine engines. Known combustors include at least one dome attached to a combustor liner that defines a combustion zone. Fuel injectors are attached to the combustor in flow communication with the dome and supply fuel to the combustion zone. Fuel enters the combustor through a dome assembly attached to a spectacle or dome plate.
The dome assembly includes an air swirler secured to the dome plate, and radially inward from a flare cone. The flare cone is divergent and extends radially outward from the air swirler to facilitate mixing the air and fuel, and spreading the mixture radially outwardly into the combustion zone. A divergent deflector extends circumferentially around the flare cone and radially outward from the flare cone. The deflector prevents hot combustion gases produced within the combustion zone from impinging upon the dome plate.
During operation, fuel discharging to the combustion zone combines with air through the air swirler and may form a film along the flare cone and the deflector. This fuel mixture may combust resulting in high gas temperatures. Prolonged exposure to the increased temperatures increases a rate of oxidation formation on the flare cone, and may result in melting or failure of the flare cone.
To facilitate reducing operating temperatures of the flare cone, at least some known combustor dome assemblies supply cooling air for convection cooling of the dome assembly through a gap extending partially circumferentially between the flare cone and the deflector. Such dome assemblies are complex, multi-piece assemblies that require multiple brazing operations to fabricate and assemble. In addition, during use the cooling air may mix with the combustion gases and adversely effect combustor emissions.
Because the multi-piece combustor dome assemblies are also complex to disassemble for maintenance purposes, at least some other known combustor dome assemblies include one-piece assemblies. Although these dome assemblies facilitate reducing combustor emissions, such assemblies do not supply cooling air to the dome assemblies, and as such, may adversely impact deflector and flare cone durability.
In an exemplary embodiment, a one-piece deflector-flare cone assembly for a gas turbine engine combustor facilitates extending a useful life of the combustor in a cost-effective and reliable manner without sacrificing combustor performance. The cone assembly includes an integral deflector portion and a flare cone portion. The deflector portion includes an integral opening that extends circumferentially through the deflector portion for receiving cooling fluid therein. The deflector opening is also circumferentially in flow communication with the flare cone portion.
During operation, cooling fluid supplied through the deflector opening is used for impingement cooling a portion of the flare cone. The impingement cooling facilitates reducing an operating temperature of the flare cone, and thus facilitates extending a useful life of the flare cone. Furthermore, because the operating temperature of the flare cone is reduced, a rate of oxidation formation on the flare cone is also reduced. Additionally, cooling fluid discharged through the opening is also used for circumferentially film cooling the deflector. The deflector facilitates reducing mixing between the cooling fluid and the combustion gases. As a result, the deflector opening facilitates reducing combustor operating temperatures to improve combustor performance and extend a useful life of the combustor, without sacrificing combustor performance.